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Introduction, Foundation Engineering
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FOUNDATION ENGINEERING
BCE III/I
Anand PantaBE(Civil), MS (Geomechanics)
Lecturer and Deputy Head
Department of Civil Engineering
Kantipur Engineering College
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FOUNDATION ENGINEERINGOBJECTIVES: To be familiar with the basic concepts and tools used
to determine structure/ foundation/ soil interactions Analyze the behavior of geotechnical structures
under static loads, this includes: Soil Exploration Shallow Foundation Deep Foundation Retaining structures <<Gravity walls>> Retaining structures <<Flexible walls>> Soil arching Soil improvements
Determine the behavior involved in these structures Present the design methods
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WHAT ARE THE GEOTECHNICAL STRUCTURES?o Foundations
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RETAINING STRUCTURESo Gravity walls
Gabion wall
Concrete wallReinforced concrete walls
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Sheet pile walls
Coffer dam
RETAINING STRUCTURES
o Flexible Walls
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GENERAL OUTLINE
Marks distribution
Full Marks(125)
Theory(100)
Final(80)
Internal (20)
Practical(25)
Final (80) Final examination by IOEInternal (20) Attendance & Tutorials(20%)+Class Test (30%)+ Assessment II(50%)Practical (25) Report (Observation Tour of a site investigation project)+Objective test
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GENERAL OUTLINE: SYLLABUS
Syllabus
Chapter Title Lecture
Hours
Marks
1 Introduction 1 2
2 Soil Exploration 6 12
3 Lateral Earth Pressure Theories and Retaining Walls
10 16
4 Arching in Soils and Braced Cuts 3 4
5 Flexible Retaining Structures and Coffer Dams
3 4
6 Bearing Capacity and Settlement of Shallow Foundation
6 12
7 Mat Foundations 3 6
8 Pile Foundations 6 12
9 Well Foundations 4 8
10 Foundation Soil Improvements 3 4
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GENERAL OUTLINE
Reference Books1. “Foundation Analysis and Design” Joseph E.Bowels. McGraw-Hill International
Editions, Fifth Edition, 1997
2. “Principles of Foundation Engineering” Braja M. Das, Fifth Edition, 2003.
3. “Basic and Applied Soil Mechanics” Gopal Ranjan and ASR Rao, Second Edition New Age International Publishers, 2000
4. “Soil Mechanics and Foundation Engineering” K.R. Arora Standard Publisher Distribution 1997
5. “A Text Book of Soil Mechanics and Foundation Engineering in SI units” VNS Murthy UBS Publishers Distributors Ltd. Fourth Edition 1993
6. “Pile Foundation Analysis and Design”, H.G. Poulos and E.H. Davis, John and sons 1980
7. “A Text Book of Foundation Engineering” Dr. R.K. Poudel and R. Neupane.
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CHAPTER 1 INTRODUCTION1.1 Foundation Engineering, Importance and purpose Foundation
Substructure elements, used to transfer the load of a structure(self weight +other actions) to the soil
Correspond to either limited loads or good quality soil (strength and stiffness)
Different geometries
Reinforced concrete
Two main aspect of the behavior: Ultimate limit failure: bearing capacity Serviceability limit: settlement
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WHY FOUNDATION ENGINEERING IS IMPORTANT?
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Pile failure due to earthquake
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DIFFERENTIAL SETTLEMENT
The Leaning Tower of Pisa leans due to a faulty foundation.
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1.2 CLASSIFICATION AND GENERAL REQUIREMENT
Classification
Foundation
Shallow
Spread or Isolated Footing
Strip or wall Footing
Combined Footing Strap Footing Mat
foundation
Deep
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CLASSIFICATION
Strap
W
•Terzaghi(1943)If D/B<1, shallow•If D/B>1 & <15, moderately deep•If D/B>15, deep Foundation
Strip Footing (L>>B)
Strap footing Raft foundation
Isolated footing
o Shallow Foundation
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DEEP FOUNDATION
Pile Foundation
End bearing pile Friction pile
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GENERAL REQUIREMENT
Location and depth criteria
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SETTLEMENT CRITERIA
Differential settlement Example: Leaning Tower Of
Pisa non-uniform, sponge-like
saturated clay soil
The Leaning Tower of Pisaleans due to a faulty foundation.
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SETTLEMENT CRITERIA
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SETTLEMENT CRITERIA
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Shear failure criteria or bearing capacity criteria
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1.3 FACTORS INFLUENCING THE CHOICE OF FOUNDATION
Principal Factors:• Function of structure• Load on foundation• Subsurface condition• Cost
Other factors:• Need of client or owner• Type of super structure• Environmental considerations• Margin of safety• Risk Level• Service life
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1.4 SELECTION OF FOUNDATION TYPE
Steps to select a foundation1. Obtain information concerning the nature of the
super-structure and loads to be transmitted2. Determine the subsurface condition3. Engineering judgment for suitable type of
foundation4. Detailed study and tentative design of most
promising types of foundation5. Prepare cost estimate of each promising type
and choose best with respect to performance and cost
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SAMPLE QUESTIONS
Describe with sketches the various types of shallow foundations. Explain under what circumstances they are used.
Describe various factors that affect foundation selection. Explain the step by step procedure for the selection of a suitable in a given situation.
What are the fundamental requirements of foundation selection?
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Thank you for your attention!